Forwarded from MinecraftModDevelopment/MMD-Dev-Server#133 by @Tat2soupRhero :

Screens disappear when looking down from them

input from @p455w0rd :
I believe TileEntity#getMaxRenderDistanceSquared takes care of this. It's either that or
TileEntity#getRenderBoundingBox ..can't quite recall atm...

Do you have a screenshot that shows this?

I do not. I believe it is fixed now. Thanks!